(a) Technical Field of the Invention
The present invention is related to an engine carburetor freeze-proof apparatus, and more particularly, to one provided with a pipe to connect the engine to the carburetor for conducting the combustion blow-by into the carburetor to prevent the carburetor from becoming iced-up in winter.
(b) Description of the Prior Art
As illustrated in FIG. 1 of the accompanying drawings, a carburetor 1 of the prior art includes an air inlet 11, a needle valve 12 and a float chamber 13. The air inlet 11 is connected through an air filter (not illustrated); one end of the needle valve 12 is connected to the air inlet 11 and another end is located in the float chamber 13; and the fuel in the float chamber 13 must retain a certain level for the carburetor 1 to conduct evaporation. When the carburetor 1 operates, the needle valve 12 is driven by a piston 14 to spray fuel, and the fresh air introduced by the air filter enters into the air inlet 11 to evaporate the fuel ejected from the needle valve 12 and the mixture is imported into the engine for explosion to produce power to push the piston in the cylinder to conduct reciprocal movements at high speed for the engine to operate.
However, during winter time or in freezing temperatures, the wall where the air inlet 11 of the carburetor 1 contacts the piston 14 is prone to icing up resulting in the failure of the needle valve 12, and further in the prevention of the return of fuel or engine stalling; consequently, the engine is prevented from operating normally. As illustrated in FIG. 2, a freeze-proof apparatus of the prior art is provided with an external hold 21 over the carburetor 2 and two pipes 31, 32 are connected to the hood 21 via a belt transmission 3. When an air filter 4 delivers fresh air to the carburetor 2 for the engine to drive the belt transmission 3, heat generated from the belt transmission 3 at high speed flows into the hood 21 of the carburetor 2 through the pipe 31 as illustrated in FIG. 3. Accordingly, the air heated in the carburetor 2 flows back through the pipe 32 into the belt transmission 3 to complete a cycle to keep the carburetor 2 from being frozen. However, the adaptation of the hood 21 not only increases the production cost but also consumes the space in the peripheral of the carburetor 2, resulting in difficulties in the arrangement of member parts of the vehicle in the design of the body and making the demand on the capacity of the engine higher.